GCSE Chemistry and Physics: Where Strong Students Still Drop Marks

A student who scores 90 out of 100 on a GCSE science paper clearly knows the science. The last ten marks are rarely about knowledge. They go on the way answers are written: a vague word, a missing reason, a number misread from a graph.

We marked a student's GCSE Chemistry and Physics mocks this year. They scored 90 and 91 out of 100. Below are the marker's notes on the marks that were lost, word for word and anonymised, and the habit behind each one.

The chemistry paper, 90 out of 100

Question 6.2. "Saying “them” is too vague. You have to say that the layers will not be able to slide over each other."

Question 7.5. "Directly proportional means the results give a perfectly straight line through the origin."

Question 7.8. "The graph was misread. The value should have been 0.24 g, not 2.4 g. Your moles calculation was correct, but it used the wrong value."

Question 8.4. "The equation was misread. There should have been 4 H-S bonds broken, with 4 H-O and 4 S=O bonds in the products."

The physics paper, 91 out of 100

Question 2.3. "You needed to state the changes to make, rather than identify any changes."

Question 3.2. "You needed to say why, which is that the resistance of R would increase."

Question 9.4. "Saying “less” is not enough. You need to mention the frequency of collisions."

The habits behind the lost marks

Name the thing. "Them" and "it" cost marks because the examiner cannot give credit for something the student has not named. Replacing every pronoun in an answer with the noun it stands for is a quick fix that works across every science paper.

Learn definitions word for word. Some terms, such as directly proportional, have an exact definition the mark scheme looks for. A list of key definitions, tested once a week, protects these marks.

Read data twice. Two of the chemistry marks went on a misread graph and a misread equation, and the method afterwards was correct. Reading the value, then reading it again before using it, costs five seconds.

Answer the command word. State, describe, explain and evaluate each ask for something different. "State the changes" wants the changes themselves, not a general comment.

Finish the explanation with a reason. When a question says explain, the mark is usually in the word because. The physics answer that lost a mark on 3.2 described what happened, but not why.

Use the keyword the mark scheme wants. On question 9.4, "less" was not enough. The mark was for frequency of collisions. Most topics have two or three of these phrases, and students who know them write shorter answers that score more.

How to use this at home

After each past paper, ask your child to sort every lost mark into two piles, "did not know it" and "knew it but did not write it properly". For strong students, the second pile is usually bigger, and it is the faster one to fix. Picking one habit from the list above each week, and checking for it on the next paper, is enough to move a score by several marks.

Getting a paper marked by a teacher who writes notes like the ones above shows exactly which habits your child needs. Our mock marking service does this for any science paper from AQA, Edexcel, OCR, Eduqas or Cambridge IGCSE, from £39.99 a paper.

One to one science lessons

Our online GCSE science tutor, Waleed Zulfiqar, is a former Head of Science with over ten years of teaching in UK schools, more than 1,200 hours of one to one tuition and two Master's degrees, in Science and in Education. He teaches biology, chemistry and physics for AQA, Edexcel, OCR and Cambridge IGCSE, and works on exactly these habits alongside the science itself.

Lessons are £270 a month for a 60 minute lesson each week, or £650 a month for maths, English and science together. Book a free consultation to talk about where your child is.

Aadam, SHLC Tutors